From what Mr Krishna told the Rajya Sabha on April 21, it appears that he has allowed himself to be satisfied by the Chinese assurance that the “small-sized” project “will have no impact on the downstream flow of the river into India.” Our experts disagree. They think it is the thin end of the wedge: the beginning of a slew of such projects on the river where it originates from the glaciers of Mount Kailash.

Before going into the reason of their fears, it is worth recalling that as far back as 2006, the media reported that the Chinese were planning to construct five dams on the river. The one at Zangmu, a 510 MW hydro project, was inaugurated a year ago - on March 16 last year, to be precise. The others were to come up at Gyatsa or Jiacha, Zhongla, Jiexu and Langzhu. It was also reported at the time that the Chinese were planning to divert 200 billion cubic metres (cumecs) of water to feed the Yellow River. The Chinese continued to deny routinely all such reports, though satellite pictures gave irrefutable evidence to the contrary.

Experts say that the withdrawal of huge quantities of water from the Brahmaputra in Tibet will definitely have a negative impact not only on India but also on Bangladesh into which the Brahmaputra flows down from Dhubri in Assam. The Indian States to be affected are Arunachal Pradesh and Assam.

It is worth recalling here some basic facts about the river. According to Prof D. C. Goswami of the Department of Environmental Sciences, Guwahati University, the Brahmaputra has a drainage area of 5,80,000 km2 , of which 50.5 per cent lie in China, 33.6 per cent in India, 7.8 per cent in Bhutan and 8.1 per cent in Bangladesh. The hydrologic regime of the river responds to the seasonal rhythm of the monsoon and freeze-thaw cycle of the Himalayan snow in the backdrop of a “unique geo-environmental framework.” The river carries a mean annual flood discharge of 48,1603 metres (cumecs) at Pandu (Guwahati).

Since the great earthquake in Assam in 1950, silt deposition in the Brahmaputra has been heavy, reducing the river's water-bearing capacity. The result is the huge floods that devastate the Brahmaputra Valley every year during the monsoon months and cause incalculable damage to human habitations, cattle and crops.

In the view of Mr Nagen Goswami, a senior engineer who retired as the Special Secretary and Commissioner of the Water Resources Department of the Government of Assam, if huge quantities of water are diverted from the river at its source, not only will it reduce the water flow drastically downstream but, as a result, will also reduce considerably the velocity of the water current that forces some of the silt to be washed downstream. The result will be a higher rate of accumulation of silt in an already heavily silted river.

The experts find it difficult to quantify the extent of damage that will be caused by the Chinese dams because very little technical data are known about them. The Chinese made it clear to Mr Krishna that they did not have to share any information about their plans with India. Whatever information they were parting with, was solely out of a “sense of trust.”

Pointing out the paucity of information from the Chinese side, Mr D. Chatterjee, a former Senior Deputy Director-General of the Geological Survey of India, says that not only the quantity of water but also the quantity and quality of silt coming into the river from upsteam are important factors in channel morphology because “in alluvial reaches, the channel is built and maintained by the river.” In his view, the effects of the Chinese dam or dams will be known only after 25 to 30 years.

It may be recalled that the Chinese have already built hydro-power dams on the Mekong river which flows through and is a lifeline to more than 60 million people in downstream countries such as Laos, Thailand, Cambodia and Vietnam, without considering the interests of these countries. Some experts have predicted that the Mekong, the 12th longest river in the world, may eventually die. What will happen to the Brahmaputra?

New Delhi in its present mood seems to be bending over backwards to placate China and keep her in good humour. The diplomatic exigencies of the day seem to be preventing New Delhi from looking at the issue in a larger perspective and taking a long-range view. The danger is that when we eventually realize the gravity of the situation, the damage will have been done and we shall be faced with a fait accompli and be unable to do anything about it. (IPA Service)